Microelectrode Arrays for Clinical Mapping: Considerations and Brain - - PowerPoint PPT Presentation

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Microelectrode Arrays for Clinical Mapping: Considerations and Brain Recordings with 1024 Channel Arrays

Shadi A. Dayeh Integrated Electronics and Biointerfaces Lab Department of Electrical and Computer Eng. University of California San Diego sdayeh@eng.ucsd.edu http://iebl.ucsd.edu/

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A subset of slides presented in the symposium has been removed pending publication

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Brain-penetrating microelectrodes EEG sensors Brain-surface electrodes

Brain Electrodes and Brain Signals

After Nitish Thakur, Science Translational Medicine 5, 210ps17, 2013.

10 mV 100 ms

Steriade et al. J. Physiology, 2001

LFPs Intracellular potentials

Resolution (μm) Coverage (cm)

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Use of Brain Mapping Devices

• 1. Diagnostic: Clinical Mapping During

Neurosurgery

• Intractable epilepsy à delineation of the

epileptic zone

• Tumor resection
• 2. Therapeutic: Neuroprosthesis; Cortical

Interface prothesis

• Motor function disability
• Speech disorders, etc.

Hochberg et al., Nature 485, 372, 2012. https://www.neurologyadvisor.com

Movement disorders (Parkinson’s disease) Utah array

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State of the art Brain Electrodes

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Neuralink: An integrated brain-machine interface platform with thousands of channels

• Developing ultra-high bandwidth brain-machine interfaces.
• Elon Musk: Goal is to achieve “symbiosis with artificial intelligence.”
• Silent speech communications.

Implanted in a mouse cortex Implanter robot Threads Mouse preparation Device Assembly Human trials are expected in Fall of 2020.

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Nature 568, 493, 2019

Silent Communication “Speech disorders”

• Dr. Edward Chang, UCSF
• Dr. Edward Chang, UCSF

Facebook

A diffuse optical tomography headset

• Concept is to use near-infrared light to measure
• xygen saturation levels in the brain.
• By mapping blood oxygen levels to specific

brain regions, phonemes, or intent for motor movements could be decoded.

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State of the Art Clinical Mapping Device

4 mm

AdTech Inc., 256 ch clinical grid

6.4 cm 1.17 mm These large electrodes under-sample the brain activity à Smaller contacts for high spatiotemporal resolution! But scaling metal electrodes to smaller diameters for better spatial resolution compromises their recording ability.

Nature 568, 493, 2019

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Thin Electrodes:

• Compliant
• Conformal.
• Intimate contact.

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Why Impedance Matters for Recording

PEDOT/Pt

Ganji et al. Adv. Func. Mat. 27, 1703018, 2017

0.1 1 10 100 1000 10

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1000 500 D (µ

µm)

200 60

Noise Voltage (µV/Hz

1/2)

Frequency (Hz)

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Planar Pt

Cp

CPE Rs Rct Cad Cp Zamp Ref Vs Vin ZE

!

"# = %&'( %&'( )*+( %,-. -%, ! /

If Cp is large, ZE should be small

Neto et. al. Front Neurosci. 12, 715, 2018

• 1. High spatial resolution à scaling à noise
• 2. Large area coverage à parasitic

shunting à attenuation

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1000 500 D (µm) 200 60

Noise Voltage (µV/Hz

1/2)

Frequency (Hz)

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Low impedance overcomes 1/f noise

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Rivnay et al. Nat. Com. 7, 11287, 2016

PEDOT:PSS SIROF

Eick et al., 6th Int. MEA meeting, 2008

‘Everything is the Interface’: Electrodes

Trasatti et al. J. Electroanalytical Chemistry 39, 163, 1972.

Volcano Plot: Electrochemical activity vs. bond energy Surface catalytic property and surface area are both important.

+ + + +

• + - + - + + -

capacitive Faradaic (redox)

+ + + + + + + + - +

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+ -

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Outline

v Pt Nanorod (PtNR) surface microelectrode arrays.

• Structure and electrochemical properties.

v Spinal Cord Implants for Pain and Restoring Motion. v Intraoperative Monitoring:

• Epilepsy monitoring.
• Language mapping.
• Functional boundaries.

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1D Materials on Flexible Substrates

Harmand et al. Phys. Rev. Lett. 121, 166101, 2018

1 µm

This work: Pt nanorods

T>400C

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Pt Nanorod Electrodes

• Dealloying: Selective dissolution of alloys to a stable

nanoporous structure.

• J. Erlebacher et al. Nature 410, 450, 2001.

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Pt Nanorod Electrodes

20 μm

SEM

5 μm

• M. Ganji et al. Nano Lett. 19, 6244, 2019.

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Parylene C Cr Pt PtNR

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(g) (h)

! "1! " 11! " ! "! "1 1! "1 #$$ # "$$ [$!!] Pt ! "1! " 11! " ! "! "1 1! "1 #$$ # "$$ [01!] Pt ! "1! " 1! "1 [01!] Pt

2.26 Å (111) Pt 2.26 Å (111) Pt 2.26 Å (111) Pt

5 nm 1 nm

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Electrochemical Properties of PtNRs

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|Z|(10 Hz) (W)

Diameter (µm)

1.1MΩ 1.6MΩ 12MΩ

10 Hz

40μm

0.0 0.5 1.0 1.5 2.0 2.5 5 10 15 20

Time (ms)

|Power| (µW)

1

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5 10 15

Injected current (µA)

• 1.5
• 1.0
• 0.5

0.0 0.5 1.0

D = 50 µm

Voltage transient (V)

P t N R Pt

Pt

PEDOT:PSS/Pt PtNR

20 40 60 80 100 120 140 160

0.1 1 10 Current-injection limit (µA)

Diameter (µm)

e)

CIC (mC/cm2)

16X 11X

tc=ta=650μs; Eipp=max possible

• Low impedance à low noise and

better stimulation characteristics.

• Smaller voltage transients on

PtNRs à Lower power dissipation for an implant that uses PtNRs.

• M. Ganji et al. Nano Lett. 19, 6244, 2019.

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Intraoperative Neuromonitoring Audio / video and automated object tracking

Video courtesy of Hersh Kanner and Jessica Chang

Nat Neurosci 21, 1281–1289, 2018

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Small Pitch μECoG Array

50μm

30μm

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Recording Traveling Waves from the Human Brain

Angelique Paulk et al., submitted, 2019.

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Two 6-channel clinical strips PEDOT

Interictal Discharges (IID) in Epilepsy Patients: Spontaneous IID Traveling Waves

IIDs seen on both recording systems

Jimmy Yang et al., in preparation, 2019.

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Events seen similarly by each recording system – Interictal Discharges (IIDs)

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IIDs seen on both recording systems

Time (s) Time (s)

Jimmy Yang et al., in preparation, 2019.

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Interictal Discharges (IID) in Epilepsy Patients: Spontaneous IID Traveling Waves

1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 500 400 300 200 100

• 100
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Time (s) Voltage (μV) 1 128

1 128

Jimmy Yang et al., in preparation, 2019.

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Intraoperative Recording at UCSD/MGH

Youngbin Tchoe

• Dr. Ahmed Raslan, OHSU

Sharona Ben-Haim Neurosurgery, UCSD Epilepsy and Pain management & experiment design Jeff Gertsch Neurology, UCSD Chief Neurophysiologist & experiment design Joseph Ciacci Neurosurgery, UCSD Neurooncology & experiment design Joel Martin Neurosurgery MD ECE PhD in progress Implant/experiment design

Jihwan Lee Andrew Bourhis

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Acknowledgment

Fabrication in SDNI, NSF-NNCI site @ UCSD This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. NSF CAREER NSF SNM (CMMI) NSF ECCS/DMR (as of Sept. 2019)

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Massachusetts General Hospital:

• Sydney Cash
• Angelique Paulk
• Jimmy Yang
• Yangling Chou
• Dan Soper
• Ziv Williams
• Daniel Cahill
• Brian Nahed
• Pamela Jones
• Douglas Maus
• Mirela Simon
• Aaron Tripp and the IOM team
• Scot Mackeil
• Scott Farren
• The fantastic and patient OR staff

Brigham and Women’s Hospital

• Garth Rees Cosgrove
• Jung Woo Lee
• Melissa Murphy
• Li Chen
• Susan Lovell
• The fantastic and patient OR staff
• UC San Diego:
• Eric Halgren
• Sharona Ben-Haim
• Dan Cleary
• Charles Dickey
• Erik Kaestner
• Vikash Gilja
• Ian Galton
• Vincent Leung
• Joel Martin
• The fantastic and patient OR staff
• Timothy Gentner
• Nasim Vahidi
• Ezequiel Arneodo
• IEBL Lab Members at UCSD:
• Mehran Ganji
• Lorraine Hossain
• Hongseok Oh
• Yun Goo Ro
• Sang Heon Lee
• Samantha Russman
• Andrew Bourhis
• Ritwik Vatsyayan
• Youngbin Tchoe
• Jihwan Lee
• Ren Liu

Thanks to:

brain spine 1024 arrays nanowire